Until now, there hasn't been any way to purchase a data-only service besides tacking it onto an existing mobile phone plan. This is the first time in the US that a carrier, or MVNO alike, offers data only plans without requiring a phone line first. The company does plan to incorporate GSM compatible SIMs in the future but as of now, the MVNO will piggyback on Sprint's nationwide network and will be compatible with any Sprint-enabled device, phones and tablets, alike. All Nexus smartphones since the Nexus 5 all the way up to the current-gen 5X and 6P. Obviously, the Phone and Messaging apps...
Source: http://www.gsmarena.com/charge_is_a_mobile_network_for_dataonly_service-news-17228.php
